Just five. Almost five (10 june 1921 - 21 april 1926).
I think is very usual, and it's also my favourite difference. Both my parents and my maternal grandparents have this gap.

__________________I declare before you all that my whole life, whether it be long or short, shall be devoted to your service and the service of our great imperial family to which we all belong.HRH Princess Elizabeth, Cape Town, 21st April 1947

have any Royals who have older husband and younger wife who more ages and she younger.

Sara Boyce

Princess Haya of Jordan is only 30. Her husband, Shk Mohammad, cp of Dubai, UAE is 58 I believe. Plus, Princess Haya's father, King Hussein was much older than 3 of 4 of his wives. I'll have to look up their birthdays to see exactly how much older.